In their own version of musical chairs, those gathered on the ground floor of Second Story Books in Rockville on the last Saturday of each month continually move to the next chair. They reach their goal when it’s finally their turn to meet with the used bookstore’s president, Allan Stypeck.

Stypeck, who has spent 40 years appraising books and other documents, carefully handles all books, checks their conditions, scans the pages and pulls from his memory a wealth of history and recollections. Often that is enough to say what the book is worth. If not, he knows the right internet sites to determine the book’s value.

On a recent appraisal day, Stypeck examined a first edition of “Cujo” by Stephen King and immediately knew when it was published. He also reviewed a book that had an authentic signature of a few of this country’s founding fathers and another one written in German that was mandatory reading for those joining the Nazi ranks.

There can be as many as 200 people who show up to the monthly event, which has occurred at the Rockville bookstore for the past three years. Stypeck also has a used bookstore in Dupont Circle.